Experiment 1. The study of three-phase circuit when connecting the load on the scheme ?triangle?
Assemble the circuit shown in fig. 5. 3.
Fig.. 5. 3. The scheme for the study of a three-phase circuit when connecting the load under the scheme "triangle?
Close all circuit breakers. Enable the scheme modeling process. Add the simulation results to the top row of the table 5. 2.
Table 5. 2
The results of the study of three-phase circuit when connecting
in the ?triangle?
Type
load
Line and phase
voltage
Line currents
Phase currents
Uab, V
Ubc,
V
Uca, V
Ia, A
Ib, A
Ic, A
Iab, A
Ibc, A
Ica,
A
symmetric
asymmetrical
Open the switch in one of the load phases (as directed by the teacher). The readings fill in the bottom row of the table 5. 2.
Calculate the active, reactive, and full power values of the circuit for the asymmetric load experiment. The result of the calculation is compared with the sum of the wattmeter readings scheme.
For example, use an oscilloscope to plot topographical vector diagrams of voltages and currents on a complex plane for each experiment at the selected scale.
Questions
1. Name the elements of a three-phase circuit.
2. How to connect a three-phase circuit according to the scheme ?star??
3. What are the differences between the three-wire and four-wire connection scheme ?star??
4. How to connect a three-phase circuit according to the scheme ?triangle??
5. What is called symmetrical, uniform and asymmetric load?
6. How to determine the active, reactive and full power in a threephase circuit?
7. What does a vector diagram of a symmetrical three-phase receiver connected by a ?star? scheme with a neutral and without a neutral look like?
8. What does a vector diagram of an asymmetric three-phase receiver connected by a ?star? scheme with a neutral and without a neutral look like?
9. What does a vector diagram of a symmetrical three-phase receiver connected by a ?triangle? scheme look like?
10. What does a vector diagram of an asymmetric three-phase receiver connected by a ?triangle? scheme look like?
Chapter 6. Transients in chains with one
And with two energy storage devices
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Transients in circuits with one energy storage device
Transients in circuits with two energy storage devices
Transients in circuits with one energy storage device
Purpose
1. Investigation of the transient process when charging a capacitor through a resistor from a DC voltage source.
2. Investigation of the transient process at the discharge of the capacitor to the resistor.
3. Investigation of the transient process when connecting an inductor through a resistor to a DC power supply.
4. Investigation of the transient process when switching off the inductor from a DC voltage source.